Norbert Völker

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Transreal arithmetic is a total arithmetic that contains real arithmetic, but which has no arithmetical exceptions. It allows the specification of the Universal Perspex Machine which unifies geometry with the Turing Machine. Here we axiomatise the algebraic structure of transreal arithmetic so that it provides a total arithmetic on any appropriate set of(More)
This paper introduces the logical system HOL2P that extends classical higher order logic (HOL) with type operator variables and universal types. HOL2P has explicit term operations for type abstraction and type application. The formation of type application terms t [T ] is restricted to small types T that do not contain any universal types. This constraint(More)
IEC 61131-3, the world-wide standard for industrial control programming, is increasingly being used in safety-related control applications. Control loops are built from components taken from domain-specific function block libraries. Code inspection and testing are the two predominant quality assurance techniques. For highly dependable control applications,(More)
The international standard IEC 61131-3, which supports Brad Cox’ concept of “Software-ICs” 9 for industrial control programming, is increasingly being used in safety-related application domains. They include safety-instrumented functions, such as burner management, emergency shut11 down and gas leak detection, but also complex automation processes(More)
More and more technical systems are supervised, controlled and regulated by programmable electronic systems. The dependability of the entire system depends heavily on the safety of the embedded software. But the technological trend to entrust software with tasks of growing complexity and safety relevance conflicts with the lacking acceptance of rigorous(More)
This position paper discusses various issues concerning requirements and design of proof assistant user interfaces (UIs). After a review of some of the difficulties faced by UI projects in academia, it presents a high-level description of proof assistant interaction. This is followed by an exposition of use cases and object identification. Several examples(More)
The mobile agent computing paradigm has been explored by the research community over recent years; however, little research has been conducted in its use in the development of robot architectures. We have been examining the use of mobile agents as a distributed control paradigm for structuring multiple robot architectures. Although many advantages of mobile(More)